Method and circuit for detecting movements through micro-electric-mechanical sensors, compensating parasitic capacitances and spurious movements

摘要

Method for detecting movements through a micro-electric-mechanical sensor, having a fixed body and a moving mass, forming at least one first and one second detection capacitor, connected to a common node and to a first, respectively a second detection node and having a common detection capacitance at rest and a capacitive unbalance in case of a movement. The method includes the steps of: feeding the common node with a constant detection voltage of predetermined duration; generating a feedback voltage to maintain the first and the second detection node at a constant common mode voltage; generating a compensation electric quantity, inversely proportional to the common detection capacitance at least in one predetermined range; supplying the compensating electric quantity to the common node; and detecting an output quantity related to the capacitive unbalance.